title: [A finite element investigation of bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation].
abstract: OBJECTIVE
  To investigate the mechanical properties of bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation with finite element method.
  
  
  METHODS
  There was a volunteer with age of 28 years old, body height 172 cm, body weight of 60 kg and without cervical deformity by X rays. The ligamentous, nonlinear, three-dimensional finite element models of normal upper cervical spine (C0-3) was developed and validated. The destabilized model with bilateral atlantoaxial trans-articular screws and atlas laminar hooks was evaluated for quasistatic loading.
  
  
  RESULTS
  The finite element model of upper cervical spine consists of 229,047 nodes and 152,475 elements, and correlated well with experimental data for all load cases and could be used for experiment. The finite model with bilateral atlantoaxial trans-articular screws and atlas-laminar hooks predicted that the maximum Von Mises Stress was in the region in which screws penetrated the atlantoaxial articular facet. The novel instrumentation resulted in sufficient stability.
  
  
  CONCLUSIONS
  The bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation is useful and effective for atlantoaxial arthrodesis.
authors.affiliation: Department of Orthopaedics, Shanghai Changzheng Hospital, Shanghai 200003, China.
authors.forename: Zhong-Wu
authors.initials: ZW
authors.lastname: Ren
authors.forename: Bin
authors.initials: B
authors.lastname: Ni
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Song
authors.forename: Mei-Chao
authors.initials: MC
authors.lastname: Zhang
authors.forename: Xiang
authors.initials: X
authors.lastname: Guo
authors.forename: Ming-Fei
authors.initials: MF
authors.lastname: Wang
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Song-Kai
authors.initials: SK
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.forename: Chun-Sheng
authors.initials: CS
authors.lastname: Tao
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
mesh_terms: D001268:Atlanto-Axial Joint / Q000601:surgery*; D001696:Biomechanical Phenomena; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D016268:Internal Fixators; D007593:Joint Instability / Q000601:surgery*; D008297:Male; D011859:Radiography; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*